[Background] It is now well accepted that low frequency electromagnetic field (LF-EMF) would produce a variety of health effects. [Objective] The objective of this work is to further investigate the effects of LF-EMF radiation on cells’ protein expression and enzymes activities. [Methods] Saccharomyces cerevisiae was used as the research object and was continuously exposed to 50 Hz low frequency electromagnetic field in this work, then the expression of its intracellular proteins and relevant enzyme activities were analyzed. [Results] The effect of LF-EMF treatment on the activities of SOD (superoxide dismutase), CAT (catalase) and MDH (malate dehydrogenase) in S. cerevisiae appeared a trend of firstly promoted and then inhibited. LF-EMF treatment can increase 43.18% of the activity of SOD at 72 h, 12.22% of the CAT at 16 h, and 12.90% of the MDH at 20 h (P<0.05); however, no significant effects of LF-EMF treatment on the activity of ADH (alcohol dehydrogenase) and LDH (lactate dehydrogenase) were observed (P>0.05). In addition, the results of protein electrophoresis and proteomics analysis indicated that LF-EMF could change the expression level of intracellular proteins in S. cerevisiae, including significant up-regulation of 3 proteins and significant down-regulation of 9 proteins (P<0.05). [Conclusion] LF-EMF radiation can affect the activity of relevant enzymes in S. cerevisiae, and change the expression level of some intracellular proteins.